1. Field of the Invention
The present invention relates to a semiconductor device inspection and analysis method and its apparatus including particles detected therein, as well as a method for manufacturing a semiconductor device, more particularly to an effective technique for analyzing particles detected by particle inspecting equipment efficiently in semiconductor device manufacturing processes.
2. Description of the Related Art
In semiconductor device manufacturing processes, it is indispensable to find causes of defects earlier and feed back the results to the object processes and manufacturing system so as to keep and improve the expected production yield. And, to realize such the object, it is also important to find defects and analyze the inspection data using inspecting equipment.
Generally, a method for manufacturing semiconductor devices comprises a filming process for filming the substrate of each semiconductor device, a photo-process for printing circuit patterns on the semiconductor device, and an etching process for etching the films of the semiconductor device. Such semiconductor devices are manufactured by repeating those processes cyclically. In recent years, the photo-process has been changed especially so that a light for exposing patterns is being replaced with an electron beam so as to enable micro fabrication of not more than 0.2 .mu.m, as well as obtain a deeper depth of focus. In a particle check is also carried out an inspection process after the filming process is finished. This particle inspection is carried out automatically by the inspecting equipment that uses a night-vision laser light.
The inspecting equipment outputs coordinate data of each particle detected in the object semiconductor wafer to an inspection data base. After this, the inspecting equipment moves the inspected wafer onto the stage of a metal microscope or a scanning electron microscope, then moves the stage to the position corresponding to the coordinate data of the detected particle, thereby classifying the particle using the expanded image thereof. This classification work is referred to as a reviewing process. If many particles are detected under a film at this time and it cannot be judged why they are generated, the inspecting equipment selects some of those particles and analyzes the element of each of the selected particles.
The element of each particle detected under a film is analyzed as follows.
At first, the film formed on the object particle is removed, thereby exposing the object particle. Then, the cross section thereof is treated using FIB (Focused Ion Beam) equipment. The wafer containing the particle is moved onto the stage of the FIB equipment, then the stage is moved to a position corresponding to the coordinate data of the particle. After this, the film is trimmed using the FIB equipment, thereby exposing the particle. At this time, the amount and position of the FIB application are adjusted manually while a visual check is made for the detected image displayed on the FIB screen to decide whether or not the particle should be exposed.
The wafer is then moved into an element analyzer, which analyzes the element of the particle. The element analyzer is, for example, EDX (Energy Dispersive X ray) equipment, which applies an electron beam to the object particle and detects the X ray generated from the particle, thereby identifying the element thereof from its energy vector. In addition, the element analyzing is, for example, AES (Auger Electron Spectroscopy) equipment, which analyzes the element of the object particle from its energy spectrum by detecting the auger electron instead of the X ray.
The element of the object particle is identified using of such an element analyzer, thereby reasoning the cause for generating the particle by analogy so as to facilitate the semiconductor manufacturing process and system to take proper countermeasures.
The inventor of the present invention has found, however, that the element analysis of particles detected under a film as described above includes the following problems.
Concretely, since the FIB equipment is operated manually, it takes about one hour for the cross section treatment of an object particle. In addition, since the FIB equipment uses gallium ions for the beam and the gallium pollutes even normal chips including no particle after the cross section treatment, the wafer used for element analysis cannot be transferred to the next process. In other words, the wafer must be disposed after the analysis.